1. Field of the Invention
The present invention relates generally to a climate control system on a vehicle and, more specifically, to a method of initializing an in-car temperature sensor for a climate control system on a vehicle.
2. Description of the Related Art
A climate control system on a vehicle, such as a motor vehicle, maintains a condition within an occupant compartment of the vehicle at a comfortable level by providing heating, cooling and ventilation. One example of a condition is air temperature, another is air distribution, while still another is air flow rate. Typically, the comfort level is subjectively determined by an occupant of the vehicle and communicated to the climate control system via a set point or other temperature control actuator, as is known in the art.
Climate control within the occupant compartment is maintained by an integrated mechanism referred to in the art as a heating, ventilation and air conditioning (HVAC) air-handling system. In an automatic climate control system, the comfort level within the occupant compartment is automatically controlled by the HVAC air-handling system. The comfort level within the occupant compartment of the vehicle is dependent on many objective and subjective factors, such as occupant preference, vehicle operating conditions, ambient temperature, humidity level, and sun heating load. The HVAC air-handling system typically includes sensing mechanisms and actuators, for sensing conditions within the occupant compartment and maintaining the desired comfort level. One example of a sensing mechanism is an in-car temperature sensor that measures the temperature within the occupant compartment. The occupant compartment temperature sensed by the in-car temperature sensor is one of several factors used by the HVAC air-handling system in maintaining the comfort level within the occupant compartment.
Under certain vehicle operating conditions, the in-car temperature sensor may be temporarily influenced by a localized pocket of heated air in the immediate vicinity of the in-car temperature sensor that is not indicative of the actual temperature within the occupant compartment. For example, if the ambient temperature is cold, the occupant compartment is warm, and the vehicle ignition is keyed off after being operational a predetermined period of time, a pocket of localized heated air from a source such as the heater core, may temporarily heat the in-car temperature sensor. If the vehicle ignition is keyed-on within a few minutes of being keyed-off, the initial output measurement of the in-car temperature sensor may indicate a warmer temperature than the actual air temperature of the occupant compartment. The HVAC air-handling system will respond by blowing cold air out of a panel duct, since it is erroneously sensing that the comfort level is too warm. This may occur for a few minutes until the in-car temperature sensor stabilizes to the actual occupant compartment air temperature and the HVAC air-handling system readjusts the temperature of the air being blown from the ducts to a warmer temperature.
One example of an automatic climate control system is disclosed in U.S. Pat. No. 5,427,313, to Davis Jr. et al., the disclosure of which is hereby incorporated by reference. While this method of automatic climate control works, it does not compensate for inadvertent heating of the in-car temperature sensor while the vehicle ignition is temporarily keyed off. Thus, there is a need in the art to provide a method of initializing an in-car temperature sensor for a climate control system that checks for inadvertent heating of the in-car temperature sensor to prevent the blowing of cold air out of the ducts.